Polyurethane cellular materials



United States Patent 3,030,329 POLYURETHANE CELLULAR MATEREALS Charles Minor Barringer, Kennett Township, Chester County, Pa, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del a corporation of Delaware No Drawin Filed July 31, E958, Ser. No. 752,203 1 Claim. (Cl. zoo-2.5

This invention relates to novel cellular polyurethane materials and more particularly to cellular polyurethane materials which have improved insulation efficiency in that they have halogenated hydrocarbons of low thermal conductivity contained within their closed cells.

Thermal insulation is widely employed today in homes, office buildings, Warehouses, mercantile establishments, farms, factories, and the like. The number of potential applications is almost boundless. A wide variety of materials have been used for thermal insulation purposes where the maximum temperature encountered is below 50 C. In recent years foamed plastics made from polystyrene, cellulose acetate, urea-forrnaldehyde resins, phenolformalclehyde resins, polyvinylchloride, calcium algihate, and polyurethanes have been gaining acceptance. Plastic polyurethane foams are exceptionally well suited for use as thermal insulation. These polyurethane foams have other attractive properties such as excellent adhesion to a wide variety of substrates, high strength in both rigid and semi-rigid state, good impact resistance, flame resistance, and inertness toward many common solvents.

Some of the polyurethane cellular materials which have been previously prepared have been blown by carbon dioxide which is liberated when isocyanato groups react with water. Some of these foams have had a high portion of open cells, whereas others have had a high closed cell content, with these closed cells containing the carbon dioxide. It is known that the efficiency of a cellular material as an insulator depends largely on the thermal conductivity of the gas contained within the cells and that the insulation efficiency of cellular materials is increased when the cells contain a gas having a thermal conductivity lower than that of air or carbon dioxide. One of the problems encountered with polyurethanes, however, has been to provide a cellular material which will retain a gas having a low thermal conductivity over a long period of time. In addition, there is a problem of providing a convenient method whereby such cellular polyurethane materials could be prepared in places having irregular shapes.

It is an object of the present invention to provide novel polyurethane cellular materials having improved insulation eh'rciency. A further object is to provide a novel polyester polyurethane cellular material suitable for use as an insulation material at low and medium temperatures. A still further object is to provide a cellular polyurethane material which will contain a gas of low thermal conductivity over a long period of time. Another object is to provide a process for the preparation of these cellular polyurethane materials. Other objects will appear hereinafter.

These and other objects of this invention are accomplished by a polyester polyurethane cellular material prepared from (1) an anhydrous, fluid polyester polyol having a hydroxyl number of from about 350 to 500 and having an average of at least 3 hydroxyl groups per molecule, (2) an isocyanato-terminated polyester polyurethane having an average of at least 3 isocyanato groups per molecule, (3) an arylene diisocyanate, (4) a material selected from the group consisting of a polyhalogenated carbon compound and mixtures thereof, said carbon compound having a molecular weight greater than about 120 and having the formula (X),. R(F) wherein ice X is a radical selected from the group consisting of chlorine and bromine, a and b are integers at least equal to 1 with the sum of a and b being at least equal to 4; R is a polyvalent organic radical of from 1 to 4 carbon atoms with the valence of R being equal to the sum of a and b, and (5) a tertiary amine catalyst; the total number of isocyanato groups in (2) and (3) being about equal to the total number of hydroxyl groups in (1); there being at least 1 cross link for each 600 units of molecular weight of said polyurethane cellular material; there being from about 5 to 25 parts by weight of said polyhalogenated carbon compound for every parts by weight of said polyurethane cellular material, with the proviso that when a single poly halogenated carbon compound is used its boiling point at atmospheric pressure range from about 0 to about 50 C. and that when a mixture of polyhalogenated carbon compounds be used the boiling point of the mixture at atmospheric pressure range from about 0 to 50 C.; with the further proviso that the polyester polyol have a solubility at 25 C. of less than about 2% by weight in the polyhalogenated carbon compound.

The novel polyester polyurethane cellular materials of the present invention are highly cross-linked with cells which are, for the most part, non-connecting and which cells contain trapped therein a halogenated carbon vapor which has a low thermal conductivity. Consequently these cellular materials are very useful as insulation. As noted from the above definition, these materials are prepared by mixing together a polyester polyol, an isocyanato-terminated polyester polyurethane, an arylene diisocyanate, a polyhalogenated carbon material and a tertiary amine catalyst. in order to obtain a highly useful cellular material, certain limitations apply to some of these reactants as will be more particularly discussed herein after. It is to be understood that in preparing these cellular materials certain optional additives such as dispersing agents and cell stabilizers may be used. in general the novel polyurethane cellular materials of the present invention range in density of from 1.2 to about 8.0 pounds per cubic foot.

In preparing these cellular materials the various components are homogeneously dispersed by suitable means and the resulting mixture subsequently expands to yield the desired cellular structure. Generally the various components are mixed at room temperature. However it is to be understood that they may be warmed slightly to obtain a lower viscosity for more convenient handling. The polyhalogenated carbon material is added as a liquid and may be introduced with the other components at any time before heat is evolved from the mixing together of the other components. The heat of reaction liberated by urethane formation from the reaction of the polyester polyol with the isocyanato-terrninated polyester polyurethane and the arylene diisocyanate vaporizes the polyhalogenated carbon material and in general, therefore, it is not necessary for external heat to be applied. The polyhalogenated carbon material may be blended with the isocyanato-terminated polyester polyurethane or it may be added when the polyester polyol and the isocyanato-terminated polyester polyurethane are being mixed together.

The mixing of the various components may be done by hand with paddles or by conventional mechanicallydriven agitators. In order to insure dispersion of the polyhalogenated carbon material, a slight pressure may be applied at the time the other components are being mixed. As mentioned above, the heat of reaction liberated by the formation of the urethane linkages vaporizes the polyhalogenated carbon material and this acts as the blowing agent in forming the cellular structure. The resulting foam contains a high percentage of closed cells with the Eatented Mar. 5, 1963 pc y a osena t d ga b n. a e t apped therein- Sin e the polyhalogenated carbon material acts as the blowing agent, it is not necessary to use any water during the foaming operation. In fact, since the present invention is directed to a foam having improved insulation efiiciency, it is necessary that the closed cells of the polyurethane foam be filled with the polyhalogenated carbon material which has a rather low thermal conductivity rather than with carbon dioxide which is obtained when the foams are blown by the reaction of water with isocyanato groups. Consequently it is necessary that the various components used in the formation of these novel cellular materials be anhydrous.

The polyester polyols which are used in obtaining the novel cellular materials of the present invention should have a hydroxyl number of about 350 to 500 and an acid number as close to as possible. An essential feature of these. polyester polyols is that they have a solubility at 25 C. of less than about 2% by weight in. the polyhalo: genated carbon material used. It has been determined that with a solubility greater than about 2% by weight, the resulting cellular material insulation efiiciency properties over a long period of time. This polyester polyol should have an average of at least about 3 hydroxyl groups per molecule and the polyol should be selected so as to provide a degree of cross-link;

ing in the final cellular material of at least about 1 cross;

link for each 600 units of molecular weight. The degree.

of cross-linking and the relative closed-cell content of the resulting cellular material appear to be related since it has been found that as the number of cross links increases the percentage of closed cells also increases. polyol should be substantially anhydrous, and for ease of operation should be fluid at room temperature. It is to be understood that a solid polyester polyol can be used provided that it melts at or below about 40* C.

The polyesters polyol is prepared by the usual methods of condensation polymerization by reacting a molar excess of an organic polyol with a dibasic carboxylic acid. The reactants are agitated at a temperature between about 150 and 225 C. until the acid number of the mixture decreases to the desired value. A catalyst such as para-v toluene sulfonic acid may be used but it is not necessary. When the reaction is completed, the mixture obtained shouldbe heated under reduced pressure to remove any water evolved during the condensation.

The dibasic carboxylic acids useful in. preparing the polyesters have no functional groups containing active hy: drogen atoms other than their carboxylic acid groups. They are preferably saturated. Acids such as phthalic acid, terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid are suitable. Anhydrides of these acids may be used also. The polyol components or components of the polyester are preferably trihydric. Examples of suitable polyols include trimethylolethane, trimethylolpropane, 'mannitol, hexane triol, glycerine, and pentaerythritol. Small amounts of dihydric alcohols such as ethylene glycol, diethylene glycol, 1 ,2-propylene glycol, 1,4-butanediol, and; cyclohexanediol may also be used. In order that the poly: urethane foam be sufficiently rigid it is, recommended that no more than about 20% of the hydroxyl groups of the polyester used be supplied by a diol.

The isocyanato-terminated polyester polyurethanes should have an average of at least 3 isocyanato. groups per molecule and may be prepared by reacting a molar excess of an arylene diisocyanate with the polyester polyol as described above. Representative diisocyanates include compounds such as toluene-2,4-diisocyanate, 1,5-naphthalenediisocyanate, cumene-2,4-diisocyanate, 4-methoxy- 1,3-phenylene diisocyanate, 4-chloro-1,3-phenylenediisocyanate, 4-bromo-1,B-phenylenediisocyanate, 4-ethoxy-l,3.- phenylenediisocyanate, 2,4- diisocyanatodiphenylether,

will not retain improyed The polyester phenylenediisocyanate, 4,4 diisocyanatodiphenylether, benzidinediisocyanate, 4,6 dimthyl' 'lj3-phenylhediiso cyanate, 9,10-anthracenediisocyanate, 4,4-diisocyanatodibenzyl, 3,3-dimethyl 4,4 diisocyanatodiphenylmethane, 2,6 dimethyl-4,4-diisocyanatodiphenyl, 2,4-diisocyanatostilbene, 3,3'-dimethyl-4,4'-diisocyanatodiphenyl, 3,3'-dimethoxy-4,4-diisocyanatodiphenyl, 1,4 anthracenediiso: cyanate, 2,5-fiuorenediisocyanate, 1,8-naphthalenediiSocyanate, and 2,6-diisocyanatobenzfuran. It is to be understood that mixtures of two or more different diisocyanates may be employed.

Another component which is used in preparing. the novel cellular materials of this invention is an arylene isocyanate. Any of the diisocyanates described above may be employed. This diisocyanate maybe mixed with the isocyanato terniinated polyester polyurethane and" the polyester polyol or it maybe. present combination with the isocyanatoderminated polyester polyurethane itself. This situation arises when a large molar excess, i.e. an excess greater than 2:1 of arylene. diisocyanate is employed in preparing the polyester polyurethane. In prep rin he P91Y i 7 Po ureth e n h fas n t 4 mbl mp oy a m l e s of irless d isa ya t q P te p l l o f qmt bq t: t a o The; amounts of isocyanato-containing components and hydroxyl-containing components to be used in preparing the cellular materials of this invention should be selected so that the total number of isocyanato groups is about equal to the total number of; hydroxyl groups. In addition, the amounts of components to be used should be selected so that the resulting polyurethane cellular mate:. rials contain at least about 1 cross'link for each 600 units of molecular weight As mentioned above, the degree of cross-linking appears to be related to the percentage of closed cells and, in order that the cellular materials of th' inventionhave improved insulation efli ciencyfit is necessary that they contain about 70% slated l s- The polyhalogenated carbon materials which are, used in the formation o f'the cellular materials of this invention are vaporized due to'tlfe heat of reaction of urethane orma on a d wn e ue ct a the l w a n The resulting foam contains these polyhalogenated carbon materials trapped within the closed cells. These mateals may e represented y the o m la (XuRlEh, wherein X is a radical selected from the group consisting of chlorine and bromine, a and b are integers at least e ual t f w h the S o a and bein a f s e l t9. .4; R s. a. pol v l t r ic ra a of from 1 t carbon atoms with the valence of R being equal to the sum of a and b. These materials should have a molec; ular weight of greater than about 120 and they may be employed in concentrations ranging from about 5 to 25 parts by weight of; the polyurethane cellular materials. t s to. b nd rs ood. a i lso bc mp oy d- When a single polyhalogenated carbon material is used to, prepare the cellular material, the boiling point of this should range from about 0 to 50 C. at atmospheric pres: sure, Those polyhalogenated carbon materialsjwhich boil below, 0;- C. are too volatile for convenient handling during the preparation of the foam. External cooling can be applied but the isocyanate and hydroxyl groups in the composition will then react less readily to chain ex. tend and crosslink the foam. Those polyhalogenated carbon materials which boil above 50- C. at atmosphericpressure provide too little vaporv to foam the fluid polyurethane composition without application of externalheat. It is to be understood that when mixtures of poly.- halogenated carbon materials are. .used, the boiling points. of individual components may range from -30 to'9'3? C.

mixtures of these materials may,

at one atmosphere pressure provided the initial boiling 5,6;dimethylrl,3pheny1enediisocyanate, 2,4-dimethyl-L3 point of the mixture ranges from about 0 to 50* C. at. one atmosphere pressure.

Representative examples of polyhalogenated carbon materials which can be used alone are: trichloromonofiuoromethane (B.P. 23.77 C.), trichlorotrifluoroethane (B.P. 47.57), dichlorohexafluoropropane (BP. 3335.8), monochloroheptafluorocyclobutane (B.P. 25 C.), dichlorodifiuoroethylene (B.P. 20 C.) and 2,3-dichloro- 1,1,3,3-tetrafiuoropropene-1 (B.P. 47 C.). Trichloromonofiuoromethane is preferred. Representative examples of polyhalogenated carbon materials which can be used as part of a mixture initially boiling between about and 50 C. at one atmosphere pressure are: dichlorodifiuoromethane (B.P. 29.8 C.), 1,1,2,2-tetrachloro- 1,2-difiuoroethane (HP. 92.8 C.) l,2-dichloro-l,l,2,2- tetrafluoroethane (B.P. 355 C.), and 1,2-dichlorohexaiiuorocyclobutane (HP. 59.9 C.).

In preparing the novel cellular materials of this invention it is desirable to employ a tertiary amine catalyst. Concentration of the catalyst and its catalytic activity should be balanced so that a sutficient time is provided for mixing of the polyester polyol component with the isocyanato-terminated polyester polyurethane and arylene diisocyanate components. 2.0 parts by weight ofcatalyst per 100 parts by weight of polyurethane-forming components is satisfactory. The catalyst is preferably added with the polyester polyol component. Any of the tertiary amine catalysts familiar to one skilled in the art of polyurethane foam technology may be employed. These catalysts include compounds such as N-methyl morpholine, triethylamine, trimethylamine, etc.

Optional additives such as dispersing agents, cell stabilizers and surfactants may be employed in preparing the polyurethane cellular materials of this invention. Thus a finer cell structure may be obtained if water-soluble organo silicone polymers are used as surfactants. These organo silicone polymers should have a molecular weight of about 2500 to 6000 and may be obtained by condensing a polyalkoxy polysilane with the monoether of a polyalkyleneether glycol in the presence of an acid catalyst. Other surfactants such as ethylene oxide modified sorbitan monopalmitate or ethylene oxide modified polypropyleneether glycol may be used, if desired, to obtain better dispersion of the components. Representative surfactants which are water-soluble organo silicone polymers are available commercially as X-520 and X-52l from Union Carbide Corporation.

The cellular materials of the present invention, due to the fact that they have a high closed cell content and. the fact that these cells contain a polyhalogenated carbon material which has a low thermal conductivity, are highly useful insulating materials. It is only by following the teachings of this invention that it is possible to obtain a polyurethane cellular material of increased insulation eificiency, which material will retain its insulation efficiency over a long period of time. Particularly these cel-' lular materials provide suitable insulation for low and medium temperature service such as in refrigerators. The cellular material can be applied to a surface by pouring thereon the various foam-forming components and allowing the composition to expand to yield the cellular structure. This provides a convenient way whereby the insulation can be installed in places having irregular shapes.

The improved insulating efiiciency of the cellular mate rials of this invention is attributed to the low thermal conductivity of the material contained within the closed cells. The thermal conductivity of the foams prepared according to the present invention is significantly better than polyurethane foams pre iously prepared.

The following examples will better illustrate the nature of the present invention; however, the invention is not intended to be limited to these examples. Parts are by weight unless otherwise indicated.

PREPARATION OF POLYESTER POLYOL (A) A polyester polyol is made by the conventional methods In general from about 0.l'-to' of condensation polymerization by reacting 1998 parts of phthalic anhydride, 1971 parts of adipic acid, 4824 parts of trimethylolpropane and 954 parts of diethylene glycol. It has a hydroxyl number of about 431, an acid number of about 1, and a water content of about 0.04% by weight. Its maximum solubility in trichloromonofiuoromethane at 25 C. is about 0.1% by weight.

PREPARATION OF POLYESTER POLYOL (B) A polyester polyol is made by the conventional methods of condensation polymerization by reacting 406 parts of phthalic anhydride, 1790 parts of adipic acid and 3280 parts of trimethylolpropane. It has a hydroxyl number of about 414, an acid number of about 2, and a water content of about 0.1% by weight.

PREPARATION OF THE ISOCYANATO-TERMI- NATED POLYESTER POLYURETHANE COMPO' SITION (A) 2000 parts of polyester polyol (A) and 8000 parts of a toluenediisocyanate isomer mixture (80% 2,4-, 20% 2,6-) are agitated in a dry reaction vessel (protected from atmospheric water vapor by a slow sweep with dry nitrogen) for 1 hour at C. The composition has a free NCO content of about 31.8% and a Brookfield viscosity of 750 cps. at 25 C.

PREPARATION OF THE ISOCYANATO-TERMI- NATED POLYESTER POLYURETHANE COMPO- SITION (B) 4400 parts of polyester polyol (B) and 15,600 parts of a toluene diisocyanate isomer mixture (80% 2, 4-, 20% 2,6-) are mixed together at room temperature in a dry reaction vessel protected from atmospheric moisture. Heat is evolved and the temperature of the mixture rises to about 47.6. External heat is then applied to the mixture and the temperature is adjusted to 80 C. The reactants are agitated for 1 hour at 80 C. The isocyanato-terminated polyester polyurethane composition obtained has a Brookfield viscosity of 2,800 cps. at 45 C. and a free isocyanato content of 29.6%.

Example 1 (A) 98 parts of polyester polyol (A) is mixed at room temperature with 0.5 part of triethylamine and 0.3 part of a surfactant which is a water-soluble organo silicone polymer (commercially available as X52l from Union Carbide Corporation). A second mixture is prepared at room temperature'using 100 parts of the isocyanatoterminated polyester polyurethane composition (A), 0.2 part of a surfactant which is a water-soluble organo silicone polymer (commercially available as X-521 from Union Carbide Corporation) and 25 parts trichloromonofiuoromethane. The two mixtures are stirred together vigorously for 20 seconds and the foamable composition that results is poured into a mold lined with a high melting wax. The foamable composition expands to fill the mold in 1 minutes. The rigid foam (1-A) obtained is stripped from the mold and cured for 1 hour at 100 C. Its properties are given in Table I.

(B) The procedure of part A above is repeated except that 35 parts of trichloromonofluoromethane are employed. The properties of the cured foam (l-B) are given in Table I. i

(C) The procedure of part A above is repeated except that 45 parts of trichloromonofiuoromethane are employed. The properties of the cured foam (l-C) obtained are given below in Table I.

(D) 60 parts of polyester polyol (A) is mixed at room temperature with 2.8 parts of water, 0.5 part of triethylamine, and 0.3 part of a surfactant which is a water soluble organo silicone polymer (commercially available as X-521 from Union Carbide Corporation). A second mixture is prepared at room temperature using 100 parts of the isocyanato-terminated polyester polyurethane (A) and 0.2 part ot a surfactant which is. a waterfsoluble organo silicone. polymer (commercially available as X-52l from Union Carbide Corporation). The two mixtures, are, stirred together vigorously for about 2 seconds. The. foarnable composition which results is poured into a wax-lined mold where it expands to give a fine celled rigid foam (1-1) After the foam hasbeen stripped from. the mold. it is heated for 1 hour at 100 C. The properties of this foam are given in Table It (E) The foams prepared in parts A, B and C aboye are. stored at 50 C. in an air oven. The thermal conductivity. of these. teams is measured after. heat. aging. The' data obtained, which is giyeninTable I below, indi:

cates the thermal conductivity of he e o ms after. this aging period.

TABLE I-.-FOA-M PROPERTIES have? (A) 95 partsofpolyester polyol (B is mixed atroom temperature with 0.5 part 0? triethylam'ine and; 0.3 part of a surfac'tant'which is a watervsoluble Qrgano silicone poly'merT' (commercially available as X 521 from Union Carbide Corporation). Similarly, IQQparts of the is ocyanato terminated polyester. polyurethane composition, 3 725 parts of' irichiq omonofluermfietha e and 9.2 part of the surfactantwhich iS. a Water-soluble organq sili: cone polymer (commercially available as X-521 from Union Carbide Corporatioh) are agitated together at room temperature. The two mixtures thus prepared are then added. together. and stleadilfstifrred for about '40 seconds he oamable cem e iiiqv. q ine s bur into amoid, lined wi h a hi h me n wa t eit'cit h nds for 21 2,. m ut s to s r a i d 5??? W59 time: erties are, shown beloyg inf'lfable 1 1.

' (B) ei p ocedu e of pa A, a ve is -ep ted except that paItsT of trichlq qmqnoiludromethanefiseniplded in placej'of- 25. parts. The propertiespt; t efgaat btained are givenbelow. in Table II.

The pr edure ofpart ab ye t reheated excent that '45- parts of. trichlorornqnofluoromethane is employed pla ef fi 25 p rt he proper ie 9i th ee Q1 taindfare given below, in. Table II.

l 'pa of p y ethylate serbiten mq llpelmit tate; 0.3 part of dimethylethanolamine, 3 partsot water, and parts of polyester. polyol (B) are, mixed, together at room temperature. This mixture is. stirred at room temperature with 100.parts of the isocyanato termina'ted polyester polyurethane. composition (B) for, about 20, seconds. The foamable composition which results is pb'uredinto a wax-lined mold Where it expands to give a fine celled'rigid foam. Afterthe feamhasbee F PP Q from the'rnold it is heated for 1: hour. at 190? C. The properties of this foam "are given in Table, II. (E), The foams bireivaredqin parts A, B ar d- C above are aged in air'oven' atfSOi C. forv interi'lals ofz'tirne fanging'up to 18 weeks; The thermal conductiyity, of thefo'a'msi is measured at regular interyals during this time. Table llj'which shows 'thfdata' obtained, indicates the 'thermal"onductivity of these foams. after the aging period."

13 i 18 23 2. 0,4 1. as. 1. as. '3 73 46 v 2D 0. 164 0. 162 0.152

0; 169 0. 172 U. 131 0. 169 0. 175 U. 183 0. 177. o. 181 0. 19%:

0. 175 0. 175 0. 191 0.178 9. tea 0. 194

TABLE 11 0A rno-rnn'rms Percenthalogenated carbon materiaL. 0 13 18 23 Density (lbsJcu.ft.). 1. as 3.14 2.67 2.40 Percent Closed Cells 9 1 91 may/31s. 97 parts of P yeste P YQ 03 P t? O ethyl amine and 0.25 part of a surfactantwhich a Waterelu le ganqs cqne ol mer (sqm 'iall available.

as.X 52 0; from. Union Carbide Corporation) are. mixed o e er. t: oo emee aiure. hen. 00 Pa s- Q f the sc ana -te m na ed Po e er. m rethe i qqsir s tion (A), 20. parts of trichloromonollupromethane and 0.25g1iart of thesurfactantiwhieh a Water-soluble organ o silicone polymer (commercially aVailable as XES ZO froni Unio Qa bide Cc rs a n) are a itated wea hera r6915 emper u e- The two mixtures are added: together t re a oo em era er et- .55: mamable. composition obtained is then poured into a wax-linedj ld w ic s ubs u n y l v by exi e i in minutes. The propertieslofi the rigid foam. obtained are given in Table III below. i

(B) e Pr u of p t A above sr e except that 30 parts 'off'trichloroinonofluoromethanes are employed instead of 20 parts. The properties of the rigid oamob i e a e. given e cw' RU? 11 TABLE III.--FOAM PROPERTIES Foam- 3-A 3,B

Percent halogenated carbon material 11 v q Density (lbsJcu. ft.) 3. 43 2.12 Percent ClosedCells 94 1' Yield faint. (lbs/sq. in.) 8 2 Example 4 bide Corporation) are agitated together. A second mixtiir is" prepared 'by stirring together parts of the isoeyanato-terminated polyester polyurethane composition (A) 20 parts of trichlorornonofiuoromethane. The

tvyolrriixt'ures,v thus'obtiiined are added together, strongly atediorff'a'bont 30 seconds, and'poured into a mold l ne. a highlmeltingw'ax. The ffoamablecomposi tidn xpandsto fill the m'old with afine celled rigid foam, haying'fa density, of 2.12 lb./cu'. ft. The yield point is 39llb./sq. in.

""(B')I' 0.5, part of triethylarnine, 97, parts of polyester polyol (A) and, 0.5 part of a surfactant which is a'watersoluble, orgario "silicone polymer (commerciallyavailable aSlX-SZO from Union, Carbide Corporation) are mixed tp'getherat'ro'oin. temperature. Asecond mixture is prepared' by, stirring together 30 parts. of trichloromonofluoromethatief and 100 parts ofthe 'isocyanato-terminated pol esterlpolyurethane,composition (A). The two mix tflr'iesohtained-aref'added.together and agitated strongly rerso seconds. "Thefoarnable composition obtained is p.qured.into, oldQlinel'd with: a high melting wax where i fer'nrrs'jro giyj'e'. a foamhvlng a dnsit'yfof about 3.143 lb;/c,u.'ft' and a'yield point of about 76 lb./sq. in. i Example;

(A) To..98.;parts ..o, polyester, polyol, (A) is added with t r in q-a artett sthrlaeiaa. ,5, Pete Q? eiehl mtrifluoroethane and 0.3 part of a surfactant which is a water-soluble organo silicone polymer (commercially available as X52l from Union Carbide Corporation). This mixture is introduced into 100 parts of the isocyanato-terminated polyester polyurethane composition (A) containing 0.2 part of a surfactant which is a watersoluble organo silicone polymer (commercially available as X-52O from Union Carbide Corporation). The mass is stirred vigorously for 30 seconds and poured into a wax-lined mold. Foaming is allowed to proceed in a 70 C. oven. The foam filis the mold to give a rigid tackfree foam having a fine cell structure. Its properties are given in Table V below.

(B) The procedure of part A above is repeated except that 35 parts of trichlorotrifluorothane is used instead of 25 parts. The properties of the foam obtained are given in Table IV below.

TABLE IV.-FOAM PROPERTIES Foam "i -A I 5-B Percent halogenated carbon material 12.8 17.8 Density (lbs/cu. it.) 3.51 3. 06 Percent Closed Cell 94 89 Yield Point (lbs/sq. in.) 76 72 k-faetor 0. 143 0. 134

Example 6 What is claimed is:

A polyester polyurethane cellular material prepared from (1) an anhydrous, fluid polyester polyol having a hydroxyl number of from about 350 to 500 and having an average of at least 3 hydroxyl groups per molecule, said polyester polyol being prepared from a composition selected from a group consisting of (a) a composition comprising phthalic anhydride, adipic acid, trimethylolpropane and diethylene glycol and (b) a composition comprising phthalic anhydride, adipic acid and trimethylolpropane, (2) an isocyanato-terminated polyester polyurethane having an average of at least 3 isocyanato groups per molecule and prepared by reacting a molar excess of an arylene diisocyanate with a polyester polyol of the type described in (1) above, (3) an arylene diisocyanate, (4) trichloromonofluoromethane and (5) a tertiary amine catalyst; the total number of isocyanato groups in (2) and (3) being about equal to the total number of hydroxyl groups in (1); there being from about 5 to 25 parts by weight of said trichloromonofiuoromethane for every parts by weight of said polyurethane cellular material.

References Cited in the file of this patent UNITED STATES PATENTS 2,848,428 Rubens Aug. 19, 1958 2,932,621 Terry Apr. 12, 1960 2,957,832 Gmitter et a1. Oct. 25, 1960 2,962,183 Rill et al Nov. 29, 1960 FOREIGN PATENTS 1,161,239 France Mar. 17, 1958 860,109 Germ-any Dec. 18, 1952 OTHER REFERENCES B-arringer: Rigid Urethane Foams-11 Chemistry and Formulation, Dupont Elastomers Chemicals Dept. Bulletin H.R.-26, April 1958, pages 26 and 27.

Dedication 3,080,329.-0harles Minor Baw'mgeo", Kennett Township, Chester County, Pa. POLYURETHANE CELLULAR MATERIALS. Patent dated Mar. 5, 1963. Dedication filed May 11, 1964;, by the assignee, E. I. du Pont de N emours and Company. Hereby dedicates to the public the entire term of said patent.

[Ofiicial Gazette August 4, 1.964.]

Notice of Adverse Decision in Interference In Interference No. 95,290 involving Patent No. 3,080,329, C. M. Barringer, POLYURETHANE CELLULAR MATERIALS, final judgment adverse to the patentee Was rendered Feb. 17, 1969, as to claim 1.

[Ofiicz'al Gazette August 5, 1969.] 

